Ligaments are tough bands of tissue that serve to connect the articular extremities of bones or to support or retain organs in place within the body. Ligaments are typically composed of coarse bundles of dense white fibrous tissue which are disposed in a parallel or closely interlaced manner, with the fibrous tissue being pliant and flexible, but not significantly extensible. Two well-known ligaments are the anterior and posterior cruciate ligaments (i.e., the ACL and PCL), which extend between the proximal end of the tibia and the distal end of the femur. The ACL and PCL cooperate, together with other ligaments and soft tissue, to provide both static and dynamic stability to the knee.
Ligaments such as the ACL and PCL can tear or rupture for a variety of reasons, including as a result of accidents or overexertion. In fact, the injury of an ACL or PCL is a common sports-related injury. Consequently, various surgical devices and procedures have been developed for reconstructing ACLs and PCLs to restore normal function to the knee. In many instances, the ACL or PCL may be reconstructed by replacing the ruptured ligament with a graft ligament. More particularly, with such procedures, bone tunnels are typically formed in the proximal end of the tibia and the distal end of the femur, with one end of the graft ligament being positioned in the femoral tunnel and the other end of the graft ligament being positioned in the tibial tunnel. The two ends of the graft ligament are anchored in place in various ways known in the art so that the graft ligament extends between the femur and the tibia in substantially the same way, and with substantially the same function, as the original ligament. This graft ligament then cooperates with the surrounding anatomical structures so as to restore normal function to the knee.
Modular guides can be used to help form the bone tunnels in an ACL or PCL graft ligament procedure. The guides help to define a location of the tunnel to be formed in bone and subsequently direct one or more tools for drilling through the bone at the desired tunnel location. One embodiment of a modular guide 10 is provided for in FIGS. 1A and 1B. As shown, the guide 10 includes a frame 12 for receiving both a translatable arm 14 and a bullet 16. The location at which the frame 12 receives the bullet 16 is stationary, while the arm 14 is configured to translate through the frame 12 to set an angle or trajectory of one or more desired bone tunnels, as shown a tibial tunnel 6 and a femoral tunnel 8. As shown, a distal tip 16d of the bullet 16 can be positioned at a desired location for a proximal end 6p, 8p of the bone tunnel 6, 8 and an end 14d of the arm 14 can be positioned at a desired location of a distal end 6d, 8d of the same bone tunnel 6, 8. A thumb screw 18 can be provided to allow a user to lock the location of the translatable arm 14 with respect to the frame 12, thereby setting the angle or trajectory of the desired bone tunnel 6, 8.
Guides of the nature illustrated in FIGS. 1A and 1B can suffer from a number of different problems. For example, a surgeon may end up missing the predetermined target with a drill pin, which is sometimes referred to as divergence. Divergence can occur for a host of reasons. In some instances, divergence occurs because the arm of the modular guide is not securely locked in position with respect to the frame, and thus the intended angle or trajectory moves, causing the drill to miss its intended mark. Alternatively, a surgeon may accidentally disengage the thumb screw because his or her hand is holding the frame near that location in use. Still further, if a change in the intended angle or trajectory needs to be made by the surgeon intra-operatively (as opposed to pre-setting the trajectory), the surgeon may accidentally shift the distal tip of the bullet and/or the end of the arm when adjusting his or her grip to loosen and then tighten the thumb screw. Having the portion of the device that the user operates to define the trajectory coincide with the portion of the device gripped by the user during operation of the device creates and compounds these problems.
In some instances, the tunnel is formed using a retrograde reamer 19 such that after a pilot tunnel is drilled, the retrograde reamer 19 is operated from the distal end 6d, 8d to the proximal end 6p, 8p of the tunnel 6, 8 to enlarge the tunnel. Such a procedure typically involves drilling a pilot hole using the guide and bullet and then disassociating the guide from the reamer before operating the reamer so that the guide does not constrict the surgeon operating the reamer. In order to disassociate the guide from the reamer though, the bullet must first be removed by sliding it up the shaft of the retrograde reamer. Then the guide is removed and the bullet can be slid back down the shaft of the reamer so that the bullet can assist with keeping the desired trajectory of the reamer during cutting. Because of this set-up, the shaft of the retrograde reamer must be longer than would be necessary just for cutting because extra length is needed to allow the bullet to be slid far enough up the reamer 19 that the distal tip 16d of the bullet 16 is proximal of the frame 12 while still keeping the reamer at the distal end of the bone tunnel. This, in turn, allows the frame 12 to be disassociated from the bullet 16 so that the frame 12 and arm 14 can be removed from the surgical site. Of course, the extra length of the reamer can increase the likelihood of divergence due to flexing of the long retrograde reamer shaft. When divergence does occur, the surgeon will typically have to re-drill or make further adjustments to the implant, related components, and/or the surgical procedure to account for the incorrectly located bone tunnel. Such adjustments are typically less desirable than correctly drilling the tunnel to start.
Guides of the nature illustrated in FIGS. 1A and 1B are further deficient because they are not universal. A right-handed surgeon and a left-handed surgeon typically need different guides so that controls such as the thumb screw are appropriately located for the various procedures with which the guides can be used. Likewise, the configuration of existing guides do not lend themselves to be used from any side of either knee with either the right hand or left hand without modifying the device or having the surgeon contort his or her body to use the guide.
A further problem that plagues surgeons during ACL and PCL reconstruction procedures is over-drilling, i.e., extending the dill pin further distally than the desired distal end of the bone tunnel. In either procedure, but particularly during PCL repairs, it can be crucial to insure that the drill pin is not over-drilled to prevent undesirable damage to the surrounding tissue and the like. For example, during a PCL repair, over-drilling can risk damage to the femoral articular cartilage and/or can puncture the neurovascular structure in the posterior portion of the knee.
Accordingly, there remains a need for improved systems, devices, and methods for use in performing ligament repairs that decrease the risk of divergence and/or over-drilling and improve the ability for such systems, devices, and methods to be used universally, i.e., such that the same systems, devices, and methods can be used with either hand, on either knee to form tibial and femoral tunnels, while sitting or standing in the same location.